Farstad W, Hyttel P, Grøndahl C, Mondain-Monval M, Smith A J
Department of Reproduction and Forensic Medicine, Norwegian College of Veterinary Medicine, Oslo.
Mol Reprod Dev. 1993 Nov;36(3):331-7. doi: 10.1002/mrd.1080360308.
A total of 15 blue fox vixens aged 1-6 years were mated, 12 once on the first day of estrus and three a second time 48 hr after the first mating, and were killed 4 hr to 8 days following mating. Ova were collected from the oviducts, evaluated by stereomicroscopy, and studied by transmission (TEM; N = 49, 12 vixens) or scanning (SEM, N = 11, three vixens) electron microscopy. At 0-3 days after ovulation, the ova had not cleaved and were at different stages of meiotic maturation. In about one-half of these ova, representing all stages of meiotic maturation, a decondensing sperm head without nuclear envelope or a small pronucleus with partial nuclear envelope was observed. No clear relationship was found between maternal meiotic stage and the stage of paternal pronucleus formation. Sperm tails were never identified in the ooplasm. Cortical granules were released after sperm penetration at early stages of meiotic maturation. Thus the block against polyspermic penetration was activated during maturation of the oocyte. The first two-cell stage appeared 4 days after ovulation (3 days after mating), the first four-cell stage the following day (day 5), and the first eight-cell stage 6 days after ovulation (5 days after mating). In a single vixen mated late (7 days postovulation) two- to four-cell stages appeared the following day (day 8). This indicates that the time required for the first cleavage division decreases with increasing interval from ovulation to mating.(ABSTRACT TRUNCATED AT 250 WORDS)
总共15只年龄在1至6岁的蓝狐母狐进行了交配，12只在发情第一天交配一次，3只在首次交配后48小时再次交配，交配后4小时至8天处死。从输卵管收集卵子，通过实体显微镜评估，并通过透射电子显微镜（TEM；N = 49，12只母狐）或扫描电子显微镜（SEM，N = 11，3只母狐）进行研究。在排卵后0至3天，卵子未分裂，处于减数分裂成熟的不同阶段。在大约一半代表减数分裂成熟所有阶段的卵子中，观察到一个没有核膜的解聚精子头部或一个有部分核膜的小原核。未发现母本减数分裂阶段与父本原核形成阶段之间有明确关系。在卵质中从未发现精子尾部。在减数分裂成熟早期精子穿透后皮质颗粒释放。因此，在卵母细胞成熟过程中激活了防止多精受精的屏障。排卵后4天（交配后3天）出现第一个二细胞阶段，第二天（第5天）出现第一个四细胞阶段，排卵后6天（交配后5天）出现第一个八细胞阶段。在一只排卵后期交配（排卵后7天）的母狐中，第二天（第8天）出现了二至四细胞阶段。这表明第一次卵裂所需的时间随着从排卵到交配间隔时间的增加而减少。（摘要截短至250字）
